Contraceptive devices such as pessaries and diaphragms are known which are intended to remain in the vagina to block the cervical os and to occupy a position so as to remain substantially undisturbed within the vaginal cavity during sexual intercourse. Such devices should be soft and flexible in order to conform perfectly to the conformation of the vagina and to result in minimal awareness during wear and during coitus.
Various patents are directed to improvements in construction of pessaries and other such vaginal contraceptives. Two such patents are U.S. Pat. Nos. 2,851,032 and 4,198,976. U.S. Pat. No. 2,681,261 is also directed to a pessary, but of a significantly different type.
U.S. Pat. No. 2,851,032 (J. T. Friedman) discloses a pessary which is stabilized and non-shifting and is adapted to engage and deflect portions of the Fallopian tubes to ensure perfected results. This patent discloses an invention having for its objects the effective sealing of the cervix which is automatically self-adjusting for anterior and posterior positions of the uterus, as well as automatic provision for adjustment of lateral deflection of the uterus, as well as for prolapsed uterus or dropped womb. In achieving its objectives, this invention proposes a thin flexible diaphragm with an annular ring encircling the same, there being provided a depression in the posterior segment of the diaphragm and a pair of arched resilient transverse members in the diaphragm, these members being located parallel to each other with the depression being located therebetween.
James Drobish in U.S. Pat. No. 4,198,976 provides for reinforced devices which can be retained in the vagina during intercourse to deliver spermicidal surfactants and provide contraceptive benefits. In accordance with the Drobish invention a container is provided having walls which allow the passage of spermicidal surfactant monomers from within the container into the vagina. The configuration of the devices allows them to be placed in the closest possible proximity to the cervical os and this feature contributes to the contraceptive efficacy. The constructions such as to substantially surround and cap the cervical os. The structure comprises a dish-shaped back forming a reservoir and constituting a vaginal retaining means, the back being characterized by one or more thickened reinforced areas. A front face is provided capping the back to form a container with the front face constituting a transport surface which is made of a semi-permeable membrane describing the walls of the container. The container contains a spermicide which consists of an aqueous solution of a micelle-forming spermicidal surfactant compound of a concentration at or above the critical micelle concentration of the said surfactant compound. The reinforcing ribs may converge to the center of the back of the device to provide channels which direct the flow of spermicide towards the central portion of the transport surface.